Raman Spectroscopic Study of the Structural Modifications Associated with the Addition of Calcium Oxide and Boron Oxide to Silica

Kline, Jeff; Tangstad, Merete; Tranell, Gabriella

doi:10.1002/9781118359341.ch57

Cited by 3 publications

(3 citation statements)

References 17 publications

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“…The reference data to identify the IR-and Raman-active structural units was obtained from the literature. 9,27,28,32,[35][36][37] The structural analyses were performed at least three times to estimate the standard errors; the standard errors of the deconvoluted area of Raman spectroscopy are the differences between the observed spectra and the fitted spectra by Peakfit v4 program (AISN software Inc., United Kingdom). 30 Figure 4A a significantly lowered viscosity, which can be correlated with the depolymerization of the silicate structures with higher CaF 2 addition, which has been previously elucidated, 9,18,20 where CaF 2 can react with the complex silicate network structures resulting in the depolymerization of silicate rings and chains to form simple silicate network structures such as dimers and monomers.…”

Section: Viscosity Measurementsmentioning

confidence: 99%

Effect of CaF₂, B₂O₃ and the CaO/SiO₂ mass ratio on the viscosity and structure of B₂O₃‐containing calcium‐silicate‐based melts

Kim

Sohn

2019

J Am Ceram Soc

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The relationship between the viscosity and structure of B 2 O 3 -containing calciumsilicate-based mold fluxes and the effects of fluidizers including CaF 2 , CaO, and B 2 O 3 on the viscosity and their correlation with the structural aspects were studied using a rheometer with Fourier transformation infrared and Raman spectroscopy.The viscosity decreased with increasing CaF 2 addition up to 28 wt% at a fixed CaO/ SiO 2 ratio of 0.3, which was related to depolymerization. Furthermore, CaF 2 addition also affected the apparent activation energy for viscous flow, which decreased with increasing CaF 2 content to 105.1 from 151.1 kJ/mol. At higher C/S ratios, the viscosity decreased in the presence of greater Ca 2+ and O 2− supplied from CaO, which subsequently increased the activation energy to 149.7 from 122.0 kJ/mol.With regard to the B 2 O 3 -melt, polymerization of the network structure was observed by comparing the B 2 O 3 -free to 4.4 wt% B 2 O 3 content. However, the viscosity was relatively constant with increasing B 2 O 3 addition. However, the viscosity decreased due to greater simplification of the network structure above 4.4 wt% B 2 O 3 . The break temperature decreased with greater B 2 O 3 addition as the crystallization was inhibited. Furthermore, the apparent activation energy decreased as depolymerization of the network structures occurred above 4.4 wt% B 2 O 3 . K E Y W O R D SB 2 O 3 , CaF 2 , CaO/SiO 2 mass ratio, mold flux, network structure, viscosity

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Section: Viscosity Measurementsmentioning

confidence: 99%

Effect of CaF₂, B₂O₃ and the CaO/SiO₂ mass ratio on the viscosity and structure of B₂O₃‐containing calcium‐silicate‐based melts

Kim

Sohn

2019

J Am Ceram Soc

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“…This agrees with the findings of the XRD. The scattering peaks at 400–650 cm −1 are related to the bending vibrations of the Si-O-Si bonds in [SiO 4 ] [ 25 , 26 ]. The vibrations of the Si-O-Si bonds of polyadic (>5), tetragonal, and ternary rings are 442 cm −1 ,492 cm −1 and 604 cm −1 , respectively [ 27 ].…”

Section: Resultsmentioning

confidence: 99%

Solubility and Valence Variation of Ce in Low-Alkali Borosilicate Glass and Glass Network Structure Analysis

et al. 2023

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Low-alkali borosilicate glass was used as the immobilization substrate, and Ce was used to replicate the trivalent and tetravalent actinides, in order to create simulated waste glass through melt heat treatment. The valence of Ce and solubility of CeO2 in waste glass were studied as well as its network structure and thermal and chemical stability. The solubility of Ce in waste glass was examined by XRD and SEM. The network structure was examined by Raman spectroscopy. The valence of Ce was determined by X-ray photoelectron spectroscopy. Thermal analysis and product consistency (PCT) were employed to determine the thermal and chemical stability of waste glasses. The results show that the solubility of cerium in low-alkali borosilicate glasses is at least 25.wt.% and precipitates a spherical CeO2 crystalline phase when it exceeds the solid solution limit; Ce is immobilized in the glass by entering the interstices of the glass network. Depolymerization and the transition from [BO3] to [BO4] occurs when CeO2 doping levels rise. About 60 percent of Ce4+ is converted to Ce3+, and the thermal stability of glass rises then falls with the increase of CeO2. All samples exhibit strong leaching resistance, with the average mass loss of Ce at 28 days being less than 10−4 gm−2d−1.

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“…The LW band is attributed to low energy bending vibrations of bridging oxygens in a T–O–T configuration, or to angular deformation of TO 4 groups in a O–T–O configuration, where T = Si, Al and Fe, in tetrahedral rings [ 18 , 19 , 20 , 21 , 22 ]. The characteristic peaks located at 442, 492, and 604 cm −1 are attributed to mixed stretching–bending vibrational modes of Si–O–Si in large-membered (≥5), four-membered, and three membered rings, respectively [ 23 ].…”

Section: Resultsmentioning

confidence: 99%

Study on Structure and Properties of La2O3-Doped Basaltic Glasses for Immobilizing Simulated Lanthanides

et al. 2021

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The La2O3-doped basaltic glass simulated high-level waste form (HLW) was prepared by the solid-state melt method. The simulated waste La2O3 maximum loading and the doping effect on structure, thermal stability, leaching behavior, density, and hardness of basaltic glasses were studied. XRD and SEM results show that the simulated waste loading of La2O3 in basaltic glass can be up to ~46 wt.%, and apatite (CaLa4(SiO4)3O) precipitates when the content of La2O3 reaches 56 wt.%. Raman results indicate that the addition of La2O3 breaks the Si–O–Si bond of large-membered and four-membered, but the number of A13+ involved in the formation of the network increase. Low content of La2O3 can help to repair the glass network, but it destroys the network as above 26 wt.%. DSC results show the thermal stability of simulated waste forms first increases and then decreases with the increase of La2O3 content. With the increase of La2O3 content, the density of the simulated waste form increases, and the hardness decreases. The leaching chemical stability of samples was evaluated by the ASTM Product Consistency Test (PCT) Method, which show that all the samples have good chemical stability. The leaching rates of La and Fe are three orders of magnitude lower than those of the other elements. Among them, L36 has the best comprehensive leaching performance.

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Raman Spectroscopic Study of the Structural Modifications Associated with the Addition of Calcium Oxide and Boron Oxide to Silica

Cited by 3 publications

References 17 publications

Effect of CaF₂, B₂O₃ and the CaO/SiO₂ mass ratio on the viscosity and structure of B₂O₃‐containing calcium‐silicate‐based melts

Effect of CaF₂, B₂O₃ and the CaO/SiO₂ mass ratio on the viscosity and structure of B₂O₃‐containing calcium‐silicate‐based melts

Solubility and Valence Variation of Ce in Low-Alkali Borosilicate Glass and Glass Network Structure Analysis

Study on Structure and Properties of La2O3-Doped Basaltic Glasses for Immobilizing Simulated Lanthanides

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Raman Spectroscopic Study of the Structural Modifications Associated with the Addition of Calcium Oxide and Boron Oxide to Silica

Cited by 3 publications

References 17 publications

Effect of CaF2, B2O3 and the CaO/SiO2 mass ratio on the viscosity and structure of B2O3‐containing calcium‐silicate‐based melts

Effect of CaF2, B2O3 and the CaO/SiO2 mass ratio on the viscosity and structure of B2O3‐containing calcium‐silicate‐based melts

Solubility and Valence Variation of Ce in Low-Alkali Borosilicate Glass and Glass Network Structure Analysis

Study on Structure and Properties of La2O3-Doped Basaltic Glasses for Immobilizing Simulated Lanthanides

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Effect of CaF₂, B₂O₃ and the CaO/SiO₂ mass ratio on the viscosity and structure of B₂O₃‐containing calcium‐silicate‐based melts

Effect of CaF₂, B₂O₃ and the CaO/SiO₂ mass ratio on the viscosity and structure of B₂O₃‐containing calcium‐silicate‐based melts